Texas fire ants aren't deterred by water. I've seen them floating in balls after good rains(seldom occurrence here).
Actually, colony-mound flooding prompts this
involuntary behaviour. Under such extremes, workers will collect and encircle the queen within a floating ball of ant-bodies - thus insuring the colony's survival once dry ground is encountered (Noah-style).
To my knowledge, fire ants will not willingly attempt to traverse open water. However, I frequently encounter fire ants actively foraging on floating vegetation that completely covers surface-water. This opportunistic habit
may account for some of the limited successes where "salvinia weevils" were deployed to control invasive populations of giant salvinia (where fire ant predation on the weevil adults and larvae may have limited the effectiveness of this biological control-measure).
As for placing the feeder's legs in pails of water: I doubt if fire ants would willingly attempt a cross-water passage. But, to insure against such attempts, mixing some surfactant or dishwashing soap should render the water's surface-tension impassable - and MIGHT also incapacitate the respiration-process of mosquito larvae within the pail of water.
Personally, I pull no punches when dealing with fire ants. They are THE ENEMY, and very much hated. IMO, they can't invade a fish-feeder (or my dogs' food bowls) if they're not alive. Therefore, physical deterrents to fire ant mobility are unnecessary around my place. ADVION is my friend! Fipronil too.
